Thanks comps for the explanation
But does it mean, that some applications will run faster? And if yes, which ones?
I'm no graphic kernel developer, but as far as I can remember, Gallium3D gains from KMS (kernel mode setting), which is why it's meant to replace Mesa (well, it's already part of it).
There were only UMS (user mode setting) drivers in the past, the Xserver used to have root privs, so it could use it's own drivers to access graphic hardware "directly" with little support from the kernel. That changed with KMS, where all the drivers are in the kernel and userspace simply tells the kernel "what" to render.
The Gallium3D is around for quite some time, but it became popular due to "KMS page flipping", which is going to be in 2.6.38. I found some fairly recent phoronix article about it, hope it helps - http://www.phoronix.com/scan.php?page=a ... nded&num=1
PS: Don't trust articles older than ~10 days, gallium3d used to have pretty much poor performance not too long ago.